Motorized wheel chair drive

ABSTRACT

A motorized drive for a wheel chair includes a motor mounting having an angle bracket with one arm which is adapted to be secured to the frame of the wheel chair. A mounting plate for the motor is pivotally secured to another arm of the bracket. The motor has a drive wheel which engages a wheel of the wheel chair. A spring biased link holds the motor in a position with respect to the bracket so that the drive wheel bears against the wheel of the chair to propel the same. A control arm pivotally supported on the bracket engages the motor mounting plate to move the same so that the drive wheel is away from the wheel of the chair, to disengage the drive, and releases the mounting plate so that the drive can propel the chair.

United States Patent 1 1 1 Rosenthal et a1.

[ Jan. 22, 1974 3,225,854 12/1965 Goerner 74/207 X 3,431,994 3/1969 Wood 180/74 x FOREIGN PATENTS OR APPLICATIONS 1,116,559 11/1961 Germany 180/33 D Primary Examiner-David Schonberg Assistant Examiner-Les1ie J. Paperner Attorney, Agent, or Firm-Mueller, Aichele & Gillman N [57] ABSTRACT A motorized drive for a wheel chair .includes a motor mounting having an angle bracket with one arm which is adapted to be secured to the frame of the wheel chair. A mounting plate for the motor is pivotally secured to another arm of the bracket. The motor has a drive wheel which engages a wheel of the wheel chair. A spring biased link holds the motor in a position with respect to the bracket so that the drive wheel bears against the wheel of the chair to propel the same. A control, arm pivotally supported on the bracket engages the motor mounting plate to move the same so that the drive wheel is away from the wheel of the chair, to disengage the drive, and releases the mounting plate so that the drive can propel the chair.

10 Claims, 5 Drawing Figures MOTORIZED WHEEL CHAIR DRIVE [76] Inventors: Ben J. Rosenthal, 9140 Kildare,

Skokie, 111. 60076; Earl Matsuoka,

206 \V. Kathleen, Park Ridge, 111. 6 0068 [22] Filed: Mar. 20, 1972 [21] Appl. No.: 236,040

[52] US. Cl ISO/6.5, 74/96, 74/211, 180/74, 180/D1G. 3 [51] Int. Cl B621! 11/04 [58] Field tiSearch..." 180/65, 33 D, 64 MM, 74, DIG. 3,74/89 96,104, 207, 211, 213, 405

[56] References Cited UNITED STATES PATENTS I 2,798,565 7/1957 Rosenthal et a]. ISO/6.5 3,167,146 l/l965 Rudolph 180/74 X 2,578,886 12/1951 lsherwood et al. 180/74 X 3,139,844 7/1964 Landers 74/405 X 2,626,191 1/1953 Buckius 308/47 A 2,521,319 9/1950 Armstrong 74/405 X 2,910,873 11/1959 Bossard et al. 74/211 X 3,064,744 11/1962 Jennings 180/65 BACKGROUND OF THE INVENTION The use of motorized drive units for wheel chairs for invalids is well known, and the construction of such wheel chairs and the mounting of motor units is accomplished in various ways. One such unit is shown in US. Pat. No. 2,798,565, issued July 9, 1957 to Harry Rosenthal and George E. Slaboch.

It is desired to provide a motor drive unit which can be easily attached to a chair, so that the drive can be used with chairs of different designs. Prior mounting techniques have required permanent alterations of the wheel chair, such as by drilling holes in the frame tubing thereof, or by the addition of a mounting for the motor, thus permanently defacing the frame of the wheel chair. In addition, the frame tubing may be weakened by the alteration, and after continued use may become distorted or even broken.

Another type of motorized drive unit utilizes a drive belt between the motor and a pulley connected to a wheel of the wheel chair. This arrangement is quite cumbersome, and can result in belt slippage and breakage. Further, the aforementioned mountings are not compact and easy to install. The requirement of a belt and pulley connected to the wheel chair adds to the size of the drive equipment, thus making the structure awkward to use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a simple and compact motorized drive unit for a wheel chair.

Another object of the invention is to provide a mounting structure for a motorized drive for a wheel chair which is easily attached to a standard wheel chair without any alteration or defacing of the chair.

It is a further object of the present invention to provide a simple structure for engagement and disengagement of a motorized drive for a wheel chair.

A still further object of the invention is'to provide drive units for propelling the wheels of a folding wheel chair which when attached to the chair permit folding of the chair to a minimum width for transportation or storage.

The motorized drive for a wheel chair of the invention includes a motor mounting having an angle bracket which is adapted to be secured to the frame of the wheel chair by a detent in the arm of the bracket and a cooperating clamp. A mounting plate for the motor has a curved end receiving a bolt secured to another arm of the bracket, for pivotally mounting the plate to the bracket. The motor has a drive wheel with a rubber sleeve thereon which engages a wheel of the wheel chair. A spring biased link holds the wheel in a position with respect to the bracket so that the sleeve on the drive wheel bears against the wheel of the chair to propel the same. An arm pivotally supported on the bracket has a nub which engages the motor mounting plate to move the same so that the drive wheel is away from the wheel of the chair to disengage the device. The nub may be formed by an integral projection on the arm, or may have a separate plastic sleeve for bearing against the motor mounting, which is held in position thereon by expansion springs.

Two drive units are provided which operate with the two main wheels of the wheel chair. With the two motors mounted to engage wheels on opposite sides of a folding wheel chair, the arms for the units, which are oppositely disposed, are angularly displaced to prevent engagement of the two arms when the wheel chair is folded for transportation or storage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view illustrating a motor driven wheel chair utilizing the present invention;

-FIG. 2 is a partially cut-away view of the present invention on a wheel chair which is in a folded condition;

FIG. 3 is a side plan view in partial cross-section of the drive unit of the invention in the engaged position;

FIG. 4 is a side plan view in partial cross-section of the drive unit in the disengaged position; and

FIG. 5 is a plan view in partial cross-section of the mounting of the drive unit.

DETAILED DESCRIPTION The motorized drive for a wheel chair incorporating the present invention may be used with a wheel chair of standard construction as shown in FIGS. 1 and 2. This chair has a frame-l0, seat 12, back 14 and foot rests l6 and 18. The frame includes vertically extending tubular members 32, 34, 36 and 38 which are interconnected by members holding the seat 12 and arms 44 and 46, and lower members 52 and 54. The chair is supported on wheels 20 and 22, which have rings 24 and 26 secured thereto for propelling the same, with front wheels 28 and 30 pivotally secured to the shafts 32 and 34 to permit turning of the chair. Handle grips 40 and 42 are provided on the vertical members 36 and 38 so that the wheel chair may be conveniently moved by an attendant. Arm rests are provided on arms 44 and 46 for the riders convenience and safety.

The apparatus for propelling the chair includes drive units 48 and 50 which are mounted to the metal tubes 52 and 54, respectively, of the frame. The drive unit 48 is shown in detail in FIGS. 3 and 4. The drive units include motors 56 and 58 with drive drums 60 and 62, respectively. The drive drums have knurled outer surfaces which engage wheels 20 and 22, respectively, to cause the same to rotate. The motors are controlled, both as to speed and direction of rotation, by electrical control apparatus 64, such as disclosed in U.S.Pat. No. 2,798,565, referred to above, and U.S.' Pat. No. 3,100,860, issued Aug. 13, 1963 to Harry Rosenthal.

As shown in FIGS. 3 and 4, motor 56 is secured to metal mounting plate by four bolts 66, with the plate 70 having a curved end 72 which is pivotally supported on bolt 74 which is secured to the flanges 68 and 69' of arm 77 of the angle bracket 76 (FIG. 5). The arm 78 of bracket 76 has a detent 120 with an arcuate shape slightly smaller than the support tube 52 to provide a snug fit. The arm 78 is secured to the tubing by clamp 80 which is secured to arm 78 by bolts 84, 86, 88 and 90. The arm 78 of bracket 76 may thus be easily secured to the tubing without any modification'thereof, and yet provides a rigid mounting to prevent the motor 56 from shifting.

Because of the detent configuration, the attaching of the brackets of the drive units to the frame of the wheel chair is relatively simple. The drive units are mounted without drilling holes in the frame or otherwisesignificantly defacing the same. Since each drive unit is secured by a clamp 80 bolted to the arm 78, the drive unit may also be easily removed.

A spring biased link 92 cooperates with the motor 56 and arm 77 of bracket 76 to maintain frictional engagement of the outer knurled surface of the drive drum 60 with the wheel 20 (FIG. 3). The compression coil spring 95 engages the arm 77 and is compressed thereagainst by eye bolt 96, bolt 104, and coupling device 106. The eye bolt 96 is fitted to the cylindrical sleeve 98 about the drive shaft of the motor, and extends through aperture 100 in arm 77. A washer 97 with spring fingers which grip the sleeve 98 holds the eye bolt 96 in position. The bolt 104 extends through retainer 102 engaging one end of coil spring 95, and is threaded into device 106 for adjusting the compression of the coil spring 95. Other spring constructions can be used for holding the motor so that the drive drum 60 is resiliently held against the wheel 20 of the chair to propel the same.

A control arm 108 extends through holes 110 and 112 in the side flanges 68 and 69 of arm 77 of bracket 76 (FIG. and has a nub 114 formed by a projecting bent portion thereof which bearsagainst the mounting plate 70 to cause theplate to pivot about bolt 74, away from the wheel 20 and into the disengaged position (FIG. 4). The pivoted support, nub and actuating arm are formed from a metal rod as an integral unit. The spring biased link of the mounting applies resilient pressure to maintain the drive wheel 60 against the wheel 20 of the wheel chair, as shown in FIG. 3. The arm 108 works against this pressure to disengage the drive, when desired, and acts to positively hold the drive drum away from the wheel of the chair.

The drive unit mounting is self-contained and in the engaged position does not extend substantially beyond the outline of the motor. Only the arm 108 and spring biased link 92 extend significantly beyond the angle bracket 76. The drive unit forms a module which can be completely assembled before it is attached to the chair, and requires no connection to the chair except the clamp mounting which has been described. This is to be contrasted with prior constructions wherein the mechanism for causing engagement and disengagement of the drive requires a separate connection to the wheel chair. Although in the drawings the angle between the arms 77 and 78 of bracket 76 is 90, for use in a particular application the angle may be changed as may be required for positioning the drive unit with respect to the frame of a wheel chair. In addition, the mounting bracket 76 is extremely rigid, providing a firm support for the motor mounting plate 70.

As shown in FIG. 1, the drive units 48 and are positioned beneath the wheel chair seat, and the control arms 108 and 124 are disposed toward the front of the chair so that they may be shifted by the rider. The drive units, including the control arms, are positioned so that they do not extend beyond the periphery of the wheel chair. This is important so that they do not strike an object, such as the edge of a door, which could result in With the two drive units 48 and 50 mounted on the I wheel chair, the arms 108 and 124 are positioned so they do not engage each other when the chair is folded together, as shown in FIG. 2, regardless of whether the motors are positioned so that the drive drums are engaged or disengaged. This is accomplished by bending the arms 108 and 124 so that they extend at slightly different angles, so that they do not contact each other when the chair is folded.

It should be noted that angle bracket 76 is symmetrical, as are all other parts except the control arm, so that they can be used for a drive unit which is mounted for engagement with the wheel on either side of the wheel chair. This eliminates separate parts which might be required for the units for opposite sides of the wheel chair.

In FIG. 5 there is shown in plan view the mounting plate and bracket 76, with a portion of the mounting plate 70 broken away to show the control arm 108. This illustrates the use of a sleeve 116 on the projecting part 114 of the arm 108, which may be of plastic material, to bear against the mounting plate 70. The sleeve 116 may be held in position by two expansion springs 121 and 122, each of which is positioned between the sleeve 116 and one flange of the arm 77 of the bracket 76. Otherwise the bracket 76 and mounting plate 70 can be the same in FIG. 5 as in the other embodiments illustrated, and FIG. 5 provides a further showing of these parts.

The drive units which have been described have been found to be highly satisfactory for use in propelling a wheel chair. The units are constructed as selfcontained modules, which are compact and provide a rigid assembly which is substantially maintenance free. The units or modules are easily mounted on, and removed from, a wheel chair, requiring only a single mounting for each drive unit. The construction of the drive units which has been described is suitable for use with wheel chairs of different designs. Although the unit is extremely compact, the control arm is positioned for ready access for disengaging the drive, or engaging the same, when desired.

We claim:

1. In a wheel chair having a folding frame and first and second wheels, and including first and second motors each having drive means for engaging the wheels of the wheel chair for propelling the same, the combination including,

first and second drive units each including bracket means adapted to be secured to only one part of the frame of the wheel chair adjacent said first and second wheels, mounting means for one of the motors pivotally joined to each of said bracket means, each of said mounting means having first and second positions with respect to said associated bracket means for holding the motor in position so that the drive means thereof engages a wheel of the wheel chair in the first position and is disengaged from the wheel of the wheel chair in the second position,

each of said drive units including spring means cooperating with said bracket means thereof and adapted to engage one of the motors for applying resilient pressure to hold the drive means thereof in engagement with one wheel of the wheel chair, and

a control arm pivotally supported on each of said bracket means and having a nub engaging said associated mounting means for pivoting the motor connected thereto with respect to said bracket said first and second drive units being oppositely disposed from one another, and being angularly displaced from one another to prevent engagement therebetween when the wheel chair is folded, each of said drive units being connected to the wheel chair solely by the connection of said bracket means to one part of the frame of the wheel chair. 2. The combination of claim 1 wherein each of said control arms has a pivotal supporting portion and an integral extending operating portion, and an integral projection on said supporting portion for engaging said mounting plate.

3. A motorized drive unit for a wheelchair having a frame and first and second wheels mounted thereon, such drive unit being provided as a unitary assembly and including in combination,

bracket means having first and second ends, with said first end including clamp means for securing said bracket means to the frame of the wheelchair,

motor means having a rotary shaft withdrive wheel means thereon,

mounting means for said motor means pivotally connected to said bracket means at said second end thereof and extending toward said first end, said mounting means having first and second pivotal positions with respect to said bracket means, with said drive wheel means of said motor means being in position for driving engagement with the wheel of the wheelchair when said mounting means is insaid first position and being held away from the wheel of the wheelchair by said mounting means in said second position thereof,

spring means connected to said bracket means intermediate said ends thereof and coupled to said motor means and applying resilient pressure thereto to'hold said drive wheel means in engagement with the wheel of the wheelchair, and control means mechanically coupled to said bracket means intermediate said ends thereof and engaging said mounting means for selectively holding said mounting means in said second position, said drive unit being connected to the frame of the wheelchair solely by said clamp means, except for the driving engagement of said drive wheel means with the wheel of the wheelchair.

4. The motorized drive according to claim 3 wherein said bracket means includes a member having first and second angularly displaced arms, with a detent in said first arm thereof and a clamp oppositely disposed from said detent, and means securing said clamp to said first arm with said clamp and said arm on opposite sides of a part of the frame of the wheel chair for securing said bracket means to the frame of said wheel chair, and including means pivotally supporting said mounting means on said second arm.

5. The motorized drive unit according to claim 3 wherein said spring means includes a compression spring and an adjustable device for adjusting the force exerted thereby.

6. The combination of claim 3 wherein said mounting means includes a plate having a curved portion at one end, and a bolt secured to said bracket means and extending through said curved portion of said plate for pivotally supporting the same.

7. The combination of claim 3 wherein said bracket means comprises a member forming two angularly disposed arms, with one of said arms being adapted to fit the frame of the wheel chair for rigidly securing said bracket means thereto.

8. The motorized drive unit according to claim 3 wherein said means mechanically coupled to said bracket and to said mounting means includes a control arm pivotally supported on said bracket means and having a nub for engaging said mounting means for pivoting the same with respect to said bracket means from one, of said first and second positions to the other of said first and second positions, said arm acting to positively hold said mounting means in said second position wherein said drive wheel means is positioned away from the wheel of the wheel chair.

9. The motorized drive unit of claim 8 wherein said bracket means, mounting means, motor means, springmeans and control arm form a self-contained module which is completely assembled prior to mounting of' of said sleeve for holding thesame in position.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,186,887 Dated January 22, 197b,

lnventofls) =ien J. Rosenthal et a1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet, in the heading insert -[7] Assignee: Rosenthal Manufacturing Gomparr, Inc., Chicago, 111.,

a Corporation of Illinois Signed and sealed this 7th day of May 197 (SEAL) Attest:

EDWARD MTLETCHBR R. c. MARS-HALL DANN Attesting Officer Commissioner of Patents 'A U. 5. GOVERNMENT FRINIING OFFICE I 19, 0-36-334. l 

1. In a wheel chair having a folding frame and first and second wheels, and including first and second motors each having drive means for engaging the wheels of the wheel chair for propelling the same, the combination including, first and second drive units each including bracket means adapted to be secured to only one part of the frame of the wheel chair adjacent said first and second wheels, mounting means for one of the motors pivotally joined to each of said bracket means, each of said mounting means having first and second positions with respect to said associated bracket means for holding the motor in position so that the drive means thereof engages a wheel of the wheel chair in the first position and is disengaged from the wheel of the wheel chair in the second position, each of said drive units including spring means cooperating with said bracket means thereof and adapted to engage one of the motors for applying resilient pressure to hold the drive means thereof in engagement with one wheel of the wheel chair, and a control arm pivotally supported on each of said bracket means and having a nub engaging said associated mounting means for pivoting the motor connected thereto with respect to said bracket means from one of the first and second positions to the other of the first and second positions, said control arms supported on said bracket means of said first and second drive units being oppositely disposed from one another, and being angularly displaced from one another to prevent engagement therebetween when the wheel chair is folded, each of said drive units being connected to the wheel chair solely by the connection of said bracket means to one part of the frame of the wheel chair.
 2. The combination of claim 1 wherein each of said control arms has a pivotal supporting portion and an integral extending operating portion, and an integral projection on said supporting portion for engaging said mounting plate.
 3. A motorized drive unit for a wheelchair having a frame and first and second wheels mounted thereon, such drive unit being provided as a unitary assembly and including in combination, bracket means having first and second ends, with said first end including clamp means for securing said bracket means to the frame of the wheelchair, motor means having a rotary shaft with drive wheel meaNs thereon, mounting means for said motor means pivotally connected to said bracket means at said second end thereof and extending toward said first end, said mounting means having first and second pivotal positions with respect to said bracket means, with said drive wheel means of said motor means being in position for driving engagement with the wheel of the wheelchair when said mounting means is in said first position and being held away from the wheel of the wheelchair by said mounting means in said second position thereof, spring means connected to said bracket means intermediate said ends thereof and coupled to said motor means and applying resilient pressure thereto to hold said drive wheel means in engagement with the wheel of the wheelchair, and control means mechanically coupled to said bracket means intermediate said ends thereof and engaging said mounting means for selectively holding said mounting means in said second position, said drive unit being connected to the frame of the wheelchair solely by said clamp means, except for the driving engagement of said drive wheel means with the wheel of the wheelchair.
 4. The motorized drive according to claim 3 wherein said bracket means includes a member having first and second angularly displaced arms, with a detent in said first arm thereof and a clamp oppositely disposed from said detent, and means securing said clamp to said first arm with said clamp and said arm on opposite sides of a part of the frame of the wheel chair for securing said bracket means to the frame of said wheel chair, and including means pivotally supporting said mounting means on said second arm.
 5. The motorized drive unit according to claim 3 wherein said spring means includes a compression spring and an adjustable device for adjusting the force exerted thereby.
 6. The combination of claim 3 wherein said mounting means includes a plate having a curved portion at one end, and a bolt secured to said bracket means and extending through said curved portion of said plate for pivotally supporting the same.
 7. The combination of claim 3 wherein said bracket means comprises a member forming two angularly disposed arms, with one of said arms being adapted to fit the frame of the wheel chair for rigidly securing said bracket means thereto.
 8. The motorized drive unit according to claim 3 wherein said means mechanically coupled to said bracket and to said mounting means includes a control arm pivotally supported on said bracket means and having a nub for engaging said mounting means for pivoting the same with respect to said bracket means from one of said first and second positions to the other of said first and second positions, said arm acting to positively hold said mounting means in said second position wherein said drive wheel means is positioned away from the wheel of the wheel chair.
 9. The motorized drive unit of claim 8 wherein said bracket means, mounting means, motor means, spring means and control arm form a self-contained module which is completely assembled prior to mounting of said bracket means on a wheel chair.
 10. The motorized drive unit according to claim 8 wherein said nub on said arm includes a sleeve for engaging said mounting means, and including first and second expansion springs on said arm on opposite sides of said sleeve for holding the same in position. 